The present invention deals with the disciplines of medicinal chemistry, cardiovascular physiology, and pharmacology. Specifically, the present invention is related to decreasing known risk factors of cardiovascular disease and other related symptoms associated with increased levels of homocysteine and C-reactive protein by administering certain 2-aryl-3-aroylbenzo[b]thiophenes.
Cardiovascular disease is a major cause of death in the United States and a major source of morbidity, medical cost, and economic loss to millions of people. Two of the most common and destructive aspects of cardiovascular disease are the appearance of atherosclerosis and thrombolitic events.
In recent years, a great deal of progress has been achieved in the treatment of cardiovascular disease. This progress has been possible not only because of the advancement of therapeutic intervention in the disease mechanisms, but also through the early identification of patients at risk of developing the disease. Indeed, patient risk identification and early treatment are important features of modern medical practice. Over the last twenty years, a variety of factors and clinical parameters have been identified which correlate with either the current state or the future probability of developing cardiovascular disease. Such risk factors may include measurable biochemical or physiological parameters, e.g., serum cholesterol, HDL, LDL, fibrin levels, etc., or behavioral of life-style patterns, such as obesity, smoking, etc. (For further information see: xe2x80x9cCardiovascular risk factors in the elderlyxe2x80x9d, Kannel W., Coronary Artery Disease, 8:565-575, 1997 and references cited therein.) Risk factors most germane to the present invention are levels of homocysteine and C-reactive protein.
The intrinsic relationship between a measurable parameter or risk factor and the disease state is not always clear. In other words, it is not always clear whether the risk factor itself is causative or contributory to the disease or is instead an ancillary reflection that is indicative of the disease. Thus, a therapeutic modality, which effects a risk factor, may be directly modifying a pathological mechanism of the disease and its future course, or may be indirectly benefiting some contributory process related to the disease.
Additionally, many risk factors associated with cardiovascular disease are involved in other pathological states in either a causative or indicative role. Therefore, improvement in a particular risk factor in cardiovascular disease may have other beneficial effects in other diseases related to that risk factor. For example, several conditions are known to be associated with abnormally high homocysteine levels, including genetic defect, menopause, hypercholesterolemia, smoking, hypertension, renal failure, and deficiencies in vitamins B6, B12, and folic acid.
Of particular interest to the methods of the present invention is the reduction of cardiovascular risk factors associated with abnormally high levels of homocysteine and C-reactive protein. It has been shown in a number of clinical studies that high levels of homocysteine in the blood are positively linked with cardiovascular disease. Furthermore, in patients suffering from genetic abnormalities which cause an increase in homocysteine (homocysteinuria), there is a great increase of early onset cardiovascular disease and other pathological conditions, inter alia, occular pathologies, skeletal and peridontal abnormalities, central nervous system irregularities, etc.
Homocysteine is also an intermediate found in the biochemical pathway related to the synthesis of the amino acids glutathione, methionine, and cysteine. Abnormally high levels of homocysteine is indicative of a metabolic disorder in the biochemical synthesis of these amino acids and is, thus, predictive of disease states associated with abnormally low levels of these amino acids. For example, glutathione has known bio-protective anti-oxidant properties such as the cyto-protection of monocytes and macrophages from oxidized low density lipoproteins (LDL). The oxidative action of oxidized LDL""s on monocytes and macrophages is thought to be a pathological mechanism in atherosclerotic arterial damage.
C-reactive protein is produced by the liver in response to cytokine production. Cytokines are produced as part of an inflammatory response in the body. Thus, C-reactive protein levels are a marker of systemic inflammatory activity. Chronic inflammation is thought to be one of the underlying and sustaining pathologies in cardiovascular disease.
At menopause, with the loss of estrogen, women""s prevalence of cardiovascular disease increases. Also, the risk factors of cardiovascular disease increase, especially lipid (cholesterol and triglyceride), homocysteine, and C-reactive protein levels. Today, the most common method of preventing cardiovascular disease in post-menopausal women is Hormone Replacement Therapy (HRT). However, many women do not comply with this therapy because of the unpleasant side-effects, such as bloating, resumption of mensus, breast tenderness, fear of uterine and breast cancer, etc. Additionally, while HRT does lower cholesterol and homocysteine levels, HRT raises C-reactive protein levels. A new therapeutic agent which lowers these risk factors would be beneficial.
The present invention provides methods for decreasing levels of homocysteine and C-reactive protein in humans comprising administering to a human in need thereof an effective amount of a compound of formula I: 
or a pharmaceutical salt or solvate thereof; wherein:
R1 and R3 are independently hydrogen, methyl, benzoyl, substituted benzoyl, or C(O)-(C1-C6 alkyl);
R2 is selected from the group pyrolidin-1-yl, piperidin-1-yl, and hexamethyleneimin-1-yl; where the R2 group is optionally the N-oxide.
Further, the present invention relates to a method for inhibiting conditions or detrimental effects caused by an excess of homocysteine and/or C-reactive protein comprising administering to a human in need thereof, an effective amount of a compound of formula I, or a pharmaceutical salt or solvate thereof.
The present invention is related to the discovery that a select group of 2-aryl-3-aroylbenzo[b]thiophenes, i.e., the compounds of formula I, are useful for lowering the levels of homocysteine and C-reactive protein.
As used herein, the term xe2x80x9ceffective amountxe2x80x9d means an amount of a compound of formula I which is capable of decreasing levels of homocysteine and/or C-reactive protein and/or inhibiting conditions or detrimental effects caused by an excess of homocysteine and/or C-reactive protein.
The term xe2x80x9cestrogen deficientxe2x80x9d refers to a condition, either naturally occurring or clinically induced, where a woman can not produce sufficient estrogenic hormones to maintain estrogen dependent functions, e.g., menses, homeostasis of bone mass, neuronal function, cardiovascular condition, etc. Such estrogen deficient situations arise from, but are not limited to, menopause and surgical or chemical ovarectomy, including its functional equivalent, e.g., medication with GnRH agonists or antagonists, ICI 182780, and the like.
The term xe2x80x9cinhibitingxe2x80x9d in the context of inhibiting conditions or detrimental effects caused by an excess of homocysteine and/or C-reactive protein includes its generally accepted meaning, i.e., prohibiting, restraining, alleviating, ameliorating, slowing, stopping, or reversing the progression or severity of an increase of homocysteine and/or C-reactive protein and the pathological sequelae, i.e., symptoms, resulting from that event.
General terms used in the description of compounds herein described bear their usual meanings. For example, xe2x80x9cC1-C6 alkylxe2x80x9d refers to straight, branched, or cyclic aliphatic chains of 1 to 6 carbon atoms including methyl, ethyl, propyl, iso-propyl, cyclopropyl, n-butyl, pentyl, hexyl and the like.
The term xe2x80x9csubstituted benzoylxe2x80x9d refers to benzoyl group having one to five substituents selected independently from the group: C1-C4 alkyl, C1-C4 alkoxy, hydroxy, nitro, chloro, fluoro, or tri(chloro or fluoro)methyl.
The term xe2x80x9cpharmaceuticalxe2x80x9d when used herein as an adjective, means substantially non-toxic and substantially non-deleterious to the recipient.
By xe2x80x9cpharmaceutical formulationxe2x80x9d it is further meant that the carrier, solvent, excipients and salt must be compatible with the active ingredient of the formulation (a compound of formula I).
The term xe2x80x9cacid addition saltxe2x80x9d refers to a salt of a compound of formula I prepared by reaction of a compound of formula I with a mineral or organic acid. For exemplification of pharmaceutical acid addition salts see, e.g., Berge, S. M, Bighley, L. D., and Monkhouse, D. C., J. Pharm. Sci., 66:1, 1977.
The term xe2x80x9csolvatexe2x80x9d represents an aggregate that comprises one or more molecules of the solute, such as a formula I compound, with one or more molecules of a pharmaceutical solvent, such as water, ethanol, and the like.
The methods provided by the present invention are useful in the treatment and prevention of pathologies associated with elevated levels of homocysteine (homocysteinuria). Harmful sequelae related to homocysteinuria, inhibited by the methods of the current invention, include, but are not limited to, ocular disorders (ectopia lentis, myopia, retinal detachment, g aucoma), skeletal disorders (scoliosis, dolic ostenomelia, osteoporosis) central nervous system defects, and the like.
The methods provided by the current invention are useful in both the treatment and prevention of harmful sequelae associated with elevated levels of C-reactive protein. Since C-reactive protein serum concentration is related to levels and production of cytokines which are especially produced in inflammatory processes, the methods of the current invention are useful in treating or preventing inflammatory events and sequelae, thereof. Such inflammatory events include, but are not limited to: arthritis (osteo and rheumatoid), arterial and venous chronic inflammation, auto-immune diseases, e.g., SLE, etc., and the like.
Methods of the current invention are useful for treating or preventing pathologic sequelae of atherosclerotic or thrombotic disease. Such pathologies include, but are not limited to stroke, circulatory insufficiency, ischemic events, myocardial infraction, pulmonary thromboembolism, stable and unstable angina, coronary artery disease, sudden death syndrome, and the like.
The present invention further contemplates the use of other currently known clinically relevant agents administered to treat the pathological conditions embodied in the present invention in combination with a compound of formula I.
Moreover, the present invention contemplates that the compounds of formula I are employed in either a treatment or prophylactic modality.
A preferred embodiment of the present invention is where the human to be administered a compound of formula I is female, and more preferred is when that human female is estrogen deficient.
Another preferred embodiment of the present invention is where the condition caused by an abnormally high level of homocysteine or C-reactive protein is cardiovascular disease, especially atherosclerosis and thrombosis. A particularly preferred embodiment of the present invention is the use of a compound of formula I in an estrogen deficient women, who is receiving estrogen or HRT, for the reduction of systemic or local inflammation.
Moreover, another preferred embodiment of the present invention is the use of a pharmaceutical acid addition salt of a compound of formula I where R1 and R3 are hydrogen and R2 is pyrolidin-1-yl. More preferably, the salt is the hydrochloride. This more preferred compound is named [2-(4-hydroxyphenyl)-6-hydroxybenzo [b]thien-3-yl][4-[2-(1-pyrolidinyl)ethoxy]phenyl]methanone hydrochloride.
An even more preferred embodiment of the present invention is the use of a pharmaceutical acid addition salt of a compound of formula I where R1 and R3 are hydrogen and R2 is piperidin-1-yl. Most preferably, the salt is the hydrochloride. This most preferred compound is named [2-(4-hydroxyphenyl)-6-hydroxybenzo [b]thien-3-yl][4-[2-(1-piperidinyl)ethoxy]phenyl]methanone hydrochloride or raloxifene hydrochloride.
Compounds of formula I where R and/or R3 are hydrogen or methyl may be prepared according to known procedures, such as those detailed in U.S. Pat. Nos. 4,133,814, 4,418,068, and 5,731,342, the teachings of each are herein incorporated by reference. The compounds of formula I which are carboxylic esters (R1 and/or R3 are C(O)-(C1-C6 alkyl), benzoyl, or substituted benzoyl) may be prepared from compounds of formula I where R and/or R3 are hydrogen by methods described in U.S. Pat. No. 5,393,763, the teachings of which are herein included by reference.
The pharmaceutical acid addition salts of the invention are typically formed by reacting a compound of formula I with an equimolar or excess amount of acid. The reactants are generally combined in a mutual solvent such as diethylether, tetrahydrofuran, methanol, ethanol, isopropanol, benzene, and the like. The salts normally precipitate out of solution within about one hour to about ten days and can be isolated by filtration or other conventional methods.
Acids commonly employed to form acid addition salts are inorganic acids such as hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, phosphoric acid, and the like, and organic acids such as p-toluenesulfonic, methanesulfonic acid, ethanesulfonic acid, oxalic acid, p-bromophenylsulfonic acid, carbonic acid, succinic acid, citric acid, tartaric acid, benzoic acid, acetic acid, and the like.
Pharmaceutical formulations can be prepared by procedures known in the art, such as, for example, in EP Published Application 670162A1, published Sep. 6, 1995, and in WO 97/35571 published Oct. 2, 1997, both of which are herein incorporated by reference. For example, a compound of formula I can be formulated with common excipients, diluents, or carriers, and formed into tablets, capsules, and the like.
Examples of excipients, diluents, and carriers that are suitable for formulation include the following: fillers and extenders such as starch, sugars, mannitol, and silicic derivatives; binding agents such as carboxymethyl cellulose and other cellulose derivatives, alginates, gelatin, and polyvinyl pyrrolidone; moisturizing agents such as glycerol; disintegrating agents such as agar, calcium carbonate, and sodium bicarbonate; agents for retarding dissolution such as paraffin; resorption accelerators such as quaternary ammonium compounds; surface active agents such as cetyl alcohol, glycerol monostearate; adsorptive carriers such as kaolin and bentonire; and lubricants such as talc, calcium and magnesium stearate and solid polyethyl glycols. Final pharmaceutical forms may be: pills, tablets, powders, lozenges, syrups, aerosols, saches, cachets, elixirs, suspensions, emulsions, ointments, suppositories, sterile injectable solutions, or sterile packaged powders, depending on the type of excipient used.
Additionally, the compounds of formula I are well suited to formulation as sustained release dosage forms. The formulations can also be so constituted that they release the active ingredient only or preferably in a particular part of the intestinal tract, possibly over a period of time. Such formulations would involve coatings, envelopes, or protective matrices which may be made from polymeric substances or waxes.
The particular dosage of a compound of formula I required to decrease levels of homocysteine and/or C-reactive protein according to this invention will depend upon the particular circumstances of the conditions to be treated. Considerations such as dosage, route of administration, and frequency of dosing are best decided by the attending physician. Generally, an effective minimum dose for oral or parenteral administration of a compound of formula I is about 1, 5, 10, 15, or 20 mg. Typically, an effective maximum dose is about 800, 120, 60, 50, or 40 mg. A particularly effective amount is 60 mg of raloxifene hydrochloride (56 mg of free base) per day via an oral route of administration. Such dosages will be administered to a patient in need of treatment from one to three times each day or as often as needed to effectively decrease levels of homocysteine and/or C-reactive protein and/or inhibit conditions or detrimental effects caused by an excess of homocysteine and/or C-reactive protein.